AP showing Alert " DFS event detected"

Sming
Comes here often

AP showing Alert " DFS event detected"

hi all ,

 

one of my AP showing an alert as shown below snapshot.

Does it affect client connectivity?

does it affect Wi-Fi performance?

how to mitigate this alert to make the status of that AP green?

Sming_2-1651858439863.png

 

Sming_1-1651858360233.png

 

 

5 REPLIES 5
ww
Kind of a big deal
Kind of a big deal

It could affect clients with poor/old chipsets/drivers.

 

Easiest way is to assign a non dfs channel.

 

The other way is to investigate why the ap detect radar on this channels.  Are there more ap's in the same area using  that channels?

 

Sming
Comes here often

hi ,

can you suggest how investigate why the ap detect radar on this channels.

 

yes another AP(i.e. AP-6) using that channel 100 but that other AP-6 is far.

ww
Kind of a big deal
Kind of a big deal

You would need to analyze the spectrum on location to see if its something in the environment that triggers this.

GreenMan
Meraki Employee

I really suggest you review this documentation:   https://documentation.meraki.com/MR/Radio_Settings/Dynamic_Frequency_Selection_(DFS)

 

If you get a lot of these events (and the alert you're seeing suggests you may be) - and they prove particularly disruptive to your WiFi clients - you may prefer to stop your APs from from using the 5 GHz channels on which DFS is mandatory.   If you do want to do this, instructions are here:   https://documentation.meraki.com/MR/Radio_Settings/RF_Profiles


This should be avoided, if possible though, because having a greater number of available channels allows your APs to co-exist with reduced co-channel interference - and your WiFi can potentially perform a lot better.   It will all depend on how frequently you see these DFS events.   You can search for these specifically in the network-wide > Event log.   The Meraki Support team will help you assess the DFS situation, if you raise a case.

pjc
Building a reputation

Meraki have decided in their wisdom to highlight this alert in this new elevated way in the latest version of firmware

 

https://community.meraki.com/t5/Wireless-LAN/Radar-event-pattern-detected-across-2-channels/m-p/1433...

 

I don't like seeing my fully functional working AP's set as amber (suggesting a more serious problem) because in the past 24hrs they automatically switched from a DFS channel to a non DFS channel.  AS GreenMan says, most users will use all available channels including DFS channels to give the least channel congestion.  In the event of an air ambulance flying over the building in the middle of the night for a few seconds, and my AP's on the top floor detecting it is not a problem in my book.  I'd like to be able to switch off this alert from making my AP's appear as alerting, I didn't have it before and I don't want it now

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